From: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
To: kbusch@kernel.org, hch@lst.de, sagi@grimberg.me
Cc: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>,
linux-nvme@lists.infradead.org
Subject: [PATCH V4 3/3] nvme-pci: get rid of the division in the fast path
Date: Thu, 16 Jul 2020 17:51:39 -0700 [thread overview]
Message-ID: <20200717005139.18923-4-chaitanya.kulkarni@wdc.com> (raw)
In-Reply-To: <20200717005139.18923-1-chaitanya.kulkarni@wdc.com>
Since we have a macro for calculating the size of the ctrl page we can
remove the division in the fast path for nvme-pci in nvme_unmap_data().
Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
---
drivers/nvme/host/pci.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index 3c852a8f18ed..616db1ae137c 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -513,7 +513,8 @@ static inline bool nvme_pci_use_sgls(struct nvme_dev *dev, struct request *req)
static void nvme_unmap_data(struct nvme_dev *dev, struct request *req)
{
struct nvme_iod *iod = blk_mq_rq_to_pdu(req);
- const int last_prp = NVME_CTRL_PAGE_SIZE / sizeof(__le64) - 1;
+ const int last_prp = (NVME_CTRL_PAGE_SIZE >> ilog2(sizeof(__le64))) - 1;
+
dma_addr_t dma_addr = iod->first_dma, next_dma_addr;
int i;
--
2.26.0
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next prev parent reply other threads:[~2020-07-17 0:52 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-17 0:51 [PATCH V4 0/3] nvme: fix iod size calculation in nvme_probe() Chaitanya Kulkarni
2020-07-17 0:51 ` [PATCH V4 1/3] nvme-core: replace ctrl page size with a macro Chaitanya Kulkarni
2020-07-17 0:51 ` [PATCH V4 2/3] nvme-pci: use max of PRP or SGL for iod size Chaitanya Kulkarni
2020-07-17 0:51 ` Chaitanya Kulkarni [this message]
2020-07-17 2:32 ` [PATCH V4 3/3] nvme-pci: get rid of the division in the fast path Keith Busch
2020-07-17 2:33 ` Chaitanya Kulkarni
2020-07-20 13:21 ` [PATCH V4 0/3] nvme: fix iod size calculation in nvme_probe() Christoph Hellwig
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